Method of fabricating metallized vias with steep walls

A method for metallizing steep-walled vias extending through dielectric material to contact metallization, the method comprising:

• applying a first seed layer extending over the contact metallization and over a horizontal surface and via sidewalls of the dielectric material;
• removing at least some of the first seed layer from the contact metallization and the horizontal surface of the dielectric material while leaving a sufficient amount of the first seed layer on the sidewalls as a catalyst for subsequent application of a third seed layer on the sidewalls;
• sputtering a second seed layer over the contact metallization and the horizontal surface of the dielectric material;
• using an electroless solution to react with the first seed layer and apply the third seed layer over the sidewalls;
• and
• electroplating an electroplated layer over the second and third seed layers.